The present invention relates to a process for the in vivo recombination of homologous DNA sequences but having a considerable proportion of mismatched bases which can range particularly up to 30%.
It is thus possible to recombine individual genes, at the level of cells or of organisms of different species and genera having common ancestors.
The present invention relates also to a process for the production of organisms recombined by crosses and recombination in vivo of different organisms, species and/or genera, as well as a process for the in vivo production of hybrid genes and hence of hybrid proteins coded by the latter.
In the synthesis of DNA, errors can occur and the resulting uncomplementary pairs of bases are called mismatches. A process for the correction of errors (mismatches and non-matches of bases) in DNA, exists. This process brings into action an enzymatic system. Thus, in Escherichia coli and Salmonella typhimurium bacteria the errors are very rapidly and accurately detected by two enzymes (MutS and MutL) enabling a third enzyme (MutU) to unwind the two DNA strands and a fourth enzyme (MutH) to cut the neosynthesized strand on a sequence of DNA (GATC) itself methylated later by another enzyme (ref: 1). The most frequent errors G:T, A:C and plus or minus one base, are the most effectively repaired. The errors not or poorly detected by the enzymes Mut (G:A, C:T AND C:C in certain places) have a particular structure "opening" the two strands.
Until now, the obtaining of hybrid species or of hybrid genes ran up against numerous problems. As regards hybrid species, the most advanced attempts made in vitro in the vegetable field by fusion of cells ran up against the major problem of genetic instability. As for the obtaining of hybrid genes or enzymes, it was possible only in vitro by genetic engineering.
It is an object of the present invention to form novel hybrid species or, a fortiori, novel hybrid genes or enzymes by in vivo intergeneric and/or interspecific recombinations with increased efficiency and facility.